She was born in Colorado Springs, to Colonel Leonard L. Griggs, Jr. and Virginia Spicer. Her weight problem started when she was 11-years-old, while her father was on duty in the Vietnam War. She and her mother would stay up late into the night, watching the news from Vietnam, and eating ice cream to improve their mood.

Havey attended Parkway Central High School, graduating in 1980 and then going on to the University of Missouri, studying communications and journalism. She left college in 1984 to work for TWA as a flight attendant until 1989. Maintaining her weight at the required 125 pounds was difficult, and she often resorted to purging before weight checks.

She met her husband, a union representative, during an airline strike. They married in 1986, but her weight further increased during her pregnancy with her daughter, from 175 to 260 pounds. They later had a second child, a son. At the time of his birth, Havey, at age 32, weighed 290 pounds. Shortly after that she learned that her husband was having an affair. After divorcing from him in 1994, she made a series of lifestyle changes and went on to lose 130 pounds. She sent her story to Woman's World magazine, which published it in 1997 under the title "Now She Has Her Dream Body!" and launched her writing career. She went on to write and self-publish several diet books describing her weight-loss regimen, as well as her autobiographical Awaken the Diet Within, and "The Vice Busting Diet". In 1999, she entered and won the "Mrs. Missouri" pageant.

She worked as a "Master Motivator" for the diet-loss website eDiets.com, writing a weekly column from 1999-2006. In January 2007, she was interviewed by Dr. Mehmet Oz on XM satellite radio's "Oprah and Friends"

She currently lives in Nashville, TN, writes for CBN.com and Diet.com and serves on the board of Turn the Tide Foundation founded by Dr. David L. Katz to fight childhood obesity.

In February 2010, Havey launched her campaign to help end obesity and overweight for one million people. Her Vice Busting Diet program is being given away. Free diet plans to anyone wanting weight loss help or a free weight loss plan.

In May 2010 Julia Havey pledged to raise money for Health Corps to support the work to reverse of Obesity of Dr. Mehmet Oz's foundation. She was the #9 overall fundraiser for the O'Magazine Live Your Best Life weekend and joined Oprah Winfrey herself for the 2 mile charity walk.